CHAPTEK II. 



THE PERCHING BIRDS, Order PASSERES. 



CROWS TO HONEY-CREEPERS. 

 Families CoRVlVJE to 



THE order of Passeres, which includes by far the great majority of existing birds, 

 and especially those popularly termed song-birds, may be regarded as occupying 

 a position analogous to that held by lizards among the Reptiles, and by the 

 bony fishes in the Fishes, all its members being more or less specialised and 

 highly organised. On this account the group is now, by general consent, regarded 

 as the highest in the class. All these birds are characterised by having the palate 

 constructed on what is termed the segithognathous modification, the structure of 

 which is described and illustrated on p. 301. They are further distinguished by 

 producing their young in a helpless and nearly naked condition, having merely a 

 few patches of dow r n scattered here and there over the body. In the skeleton the 

 slender metatarsus has its three nearly equalised condyles placed almost in the 

 same transverse line ; while the arm-bone, or humerus, has a well-marked bifurcate 

 process at the outer sides of its lower end ; and, as a minor character, it may be 

 mentioned that the breast-bone has but a single notch. The first toe is always 

 present, and is mobile and directed backwards, in addition to being worked by a 

 muscle independently of the other digits. A covering of feathers invests the legs 

 as far down as the ankle-joint. There are usually twelve feathers in the tail ; 

 while the primary quills of the wings vary in number from nine to ten, the latter 

 being the usual complement among the typical members of the order. 



With three exceptions, the perching birds of the Old World belong to a section 

 characterised by having the intrinsic muscles of the syrinx, or organ of voice, 

 attached to the cords of the open rings of the bronchial tube, and technically 

 termed the Acromyodi. The Indian members of the order, provided with ten 

 primary quills in the wings, may be divided, according to an arrangement sug- 

 gested by Mr. Oates, into five groups. In the first of these the nestling resembles 

 that of the adult female ; this is likewise true of the second group, in which the 

 coloration of the young bird is more brilliant than that of its parent, being in the 

 Indian forms generally suffused with yellow. On the other hand, in the third 

 group, the nestling is transversely barred ; while in the fourth it is striated ; and 

 in the fifth group the nestling-plumage is either mottled or squamated. 



Although certain species of the perching birds, such as the snow-bunting and 

 the sand-marten, have a circumpolar distribution, numerous genera of this order 



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